WBBSE Solutions For Class 6 Geography Chapter 5 Water Land Air Topic A The Earth Its Atmosphere, Lithosphere And Hydrosphere

Class 6 Geography WBBSE Chapter 5 Water Land Air Chapter Synopsis

1. The blanket of air that envelopes the Earth and is held close to it because of the Earth’s gravitational force is called the Atmosphere. The atmosphere extends up to a height of 10000km to 15000 km above the Earth’s surface.

2. The lowest layer of the atmosphere extending up to 16km above the Earth’s surface, is known as the Troposphere.

3. The next layer after the troposphere up to a height of 50 km from the Earth’s surface is known as the Stratosphere.

4. The layer, above the stratosphere up to a height of 80 km from the Earth’s surface is known as the Mesosphere.

5. Above the mesosphere till 300 km from the Earth’s surface is the Thermosphere. Air becomes very thin in this layer. Gases in this layer are in an ionized state. So this layer is also known as the Ionosphere.

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6. The outermost layer of the atmosphere, above the thermosphere where artificial satellites and space stations are located, is known as the Exosphere.

7. The solid and thin outermost layer of the Earth is called the Crust.

8. The concentric layer in between the crust and the core is known as the Mantle.

9. The innermost layer; after the mantle around the centre of the Earth, is known as the Core.

10. The solid landmass, made up of mostly rocks and soil is known as the Lithosphere. It forms only one-quarter of the Earth’s surface.

11. The total water content of the Earth in liquid, vapour or solid form together form the Hydrosphere.

12. Three-fourths of the Earth’s surface is water. No other planet in the solar system contains water to such a great extent. Thus, Earth appears blue from space and is called the Blue planet.

13. The cyclic movement of water through solid, liquid and gaseous states from the Earth’s surface to the air and back on Earth is known as the Water cycle or the Hydrological cycle.

14. The movement of continents on the Earth’s surface under the influence of the convection currents generated in the magma present in the Earth’s interior is known as Continental drift.

15. Around 200 million years ago, there was only one unified continent or supercontinent. It was known as the Pangaea or, Pangea.

16. Pangaea was surrounded by a huge water mass or super ocean, known as the Panthalassa.

17. Difference in temperature in the Earth’s interior generates currents, known as Convention currents.

18. Land, water and air on Earth together create an environment that can support and sustain life. This region of the Earth occupied by living organisms is called the Biosphere. The numbers of plant and animal species in the biosphere are almost 35 thousand and 1.5 million respectively,

19. Human beings, an important part of the biosphere, interact with the environment. The more negative activities of human beings on the environment, the higher the degree of degradation of the environment.

20. The increase in the average temperature of the Earth’s atmosphere because of the heat trapped by the greenhouse gases in the air is called global warming.

Burning of fossil fuels and emissions from the factories lead to an increase of greenhouse gases (CO₂, CH₄, NO₂ etc.) in the atmosphere.

Class 6 Geography WBBSE Chapter 5 Water Land Air Topic A The Earth Its Atmosphere, Lithosphere And Hydrosphere Analytical Type Questions

Question 1. What is the Atmosphere? Discuss the layers of the Earth’s atmosphere.
Answer:

Atmosphere:

The layer of air that envelopes the Earth and is held close to it because of the Earth’s gravitational force is called the Atmosphere.

The Earth’s atmosphere can be divided into 5 layers depending on the difference in temperature. They are as follows—

Troposphere: The first layer of the atmosphere from the surface of the Earth.

1. The Troposphere extends to 16km above the Earth’s surface.
2. This layer experiences rainfall, storms, tornadoes, cyclones, etc.
3. The temperature in this layer decreases with an increase in altitude. The average Lapse Rate is a drop of about 6.5°celsius for every 1,000-metre increase in altitude.

Stratosphere: The stratosphere is the next layer after Troposphere.

1. The Stratosphere extends to 50km from the surface.
2. Temperature increases with an increase in altitude in this layer.
3. Dust particles and water vapour are absent in this layer.
4. This layer does not experience rainfall, storms, tornadoes or cyclones or any other weather phenomena.
5. Jet planes fly through this layer.
6. This layer is also known as the Ozonosphere because of the abundance of ozone at a height of 20 km- 25 km in this layer.

Mesosphere: The layer that is above Stratosphere is known as the Mesosphere.

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1. Extends from 50-80km above Stratosphere.
2. Temperature decreases with an increase in altitude in this layer.
3. The meteors that rush towards the Earth, burn up because of friction in this layer.

Thermosphere: The layer that follows after the Mesosphere is the Thermosphere.

1. It extends to 300km above the Earth’s surface.
2. The temperature rises rapidly in this layer. The temperature can also shoot up to 200°C.
3. The layer is also known as the Ionosphere as the UV rays and X-rays from the Sun ionise the gases in this layer.
4. Aurora’ is observed in the polar regions due to the presence of the Ionosphere.
5. The presence of the Ionosphere helps in wireless communication as Radio waves reflect back to the Earth from this layer.

 

Exosphere: This is the outermost layer of the atmosphere.

1. The layer of air extending almost 750 km above the Thermosphere is called the Exosphere.
2. This layer is rich in Helium and Hydrogen.
3. The air is very thin in this layer and gradually blends into outer space.
4. Artificial satellites and space stations are located in this layer.

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Question 2. Discuss the atmosphere.
Answer:

Atmosphere:

The atmosphere is the layer of air that envelops the Earth.

The significance of the atmosphere is as follows—

Origin of life: Life exists on Earth because of the atmosphere. The oxygen present in the atmosphere enabled the origin and sustenance of life.

Balance in temperature: Without the atmosphere, temperatures during the days would have been very high and conversely, nights would have been very cold. The atmosphere maintains the balance in temperature, making the Earth suitable for living.

Protection from meteors: The meteors that rush towards the Earth burn up because of friction with the atmosphere. If the atmosphere was not present, meteors would have hit the surface of the Earth, causing damage to life and property.

Hydrological balance: The Hydrological cycle exists because of the atmosphere. Without the atmosphere, the processes of evaporation, transpiration, condensation and precipitation would not have been possible.

Others: The other significant influences of the atmosphere are as follows:

1. Plants receive nitrogen from the atmosphere, i.e. important for their existence.
2. The disintegration of rocks for the formation of soil would not have been possible without the existence of the atmosphere.

Question 3. Make a list of everything we do with the water in our daily lives.
Answer:

Water is essential for life on Earth. Rather, life on Earth would cease to exist without water. The various uses of water in our day-to-day lives are as follows—

1. Daily Household activities: We need water daily for activities like cooking, washing clothes and utensils, gardening, bathing, cleaning, etc.

2. Habitat for aquatic creatures: There are many creatures on Earth that can survive only in water. Oceans, seas, rivers, ponds and lakes are houses to such creatures and without such waterbodies, the aquatic ecosystem would not have existed.

3. Agriculture and industries: Agricultural and industrial activities essentially require water in the entire process of production. Production of most crops can only be enhanced with proper means of irrigation in the absence of adequate rainfall.

4. Pisciculture (fish farming): Many countries (like India) use their water bodies for fish farming. They farm fish on a large scale for commercial purposes.

5. Transportation: Water transport is the cheapest mode of transport. Throughout the world, there is a huge use of waterways of the transport goods.

6. Source of minerals: Seawater contains various minerals in the solution that can be extracted later.

7. Maintain a balance of life: The entire amount of water on Earth is constant and only changes its form through various states and moves in a cyclic manner from the Earth’s surface to air and back to the Earth again.

This is the Hydrological cycle which actually helps to maintain the balance of life on Earth.

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Chapter 5 Water Land Air Topic A The Earth Its Atmosphere, Lithosphere And Hydrosphere Short Analytical Type Questions

Question 1. Why does the sky appear blue during the day and black at night?
Answer:

The sky appear blue during the day and black at night:

Numerous dust particles, water vapour and water droplets remain suspended in the atmosphere.

As white sunlight enters the atmosphere, it strikes the suspended particles – which causes the scattering of sunlight.

The light with the shorter wavelength is scattered more. The violet and blue rays are scattered and diffused the most and so, the sky appears blue during the day.

At night, in the absence of sunlight, there is no scattering of light, and thus the sky appears black.

Question 2. Write about the importance of the Earth’s atmosphere. Or, Write down anything you know about the importance of the atmosphere.
Answer:

The importance of the Earth’s atmosphere is as follows:

1. Oxygen, the main support system of life on Earth, exists in the atmosphere.
2. Plants can only carry out photosynthesis with the help of the carbon dioxide present in the atmosphere.
3. It is the atmosphere that shields living organisms on Earth from the harmful UV rays of the Sun.
4. The Water cycle would not exist without the atmosphere.

Question 3. Discuss the stratification of the atmosphere.
Answer:

Stratification of the atmosphere:

The atmosphere is divided into layers on the basis of temperature and components. On the basis of components,

The atmosphere is divided into two layers—

1. The Homosphere and
2. The Heterosphere.

Homosphere has gases of similar composition while Heterosphere has gases of heterogeneous composition.

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On the basis of temperature differences, the atmosphere is divided into six layers—

1. Troposphere,
2. Stratosphere,
3. Mesosphere,
4. Thermosphere and
5. Exosphere.

Troposphere: Troposphere is the lowest layer of the atmosphere extending for about 16km above the Earth’s surface. Here, temperature decreases with an increase in altitude.

Stratosphere: This layer extends from 16-50km above the troposphere. Temperature increases with an increase in altitude.

Mesosphere: This layer extends from 50-80 km above the stratosphere. In this layer, the temperature drops again with altitude.

Thermosphere: This layer extends from 80-300 km above the Mesosphere. The presence of an Ultraviolet ray makes the temperature shoot up to 200°C in this layer.

Exosphere: This layer extends from 300km above the Thermosphere. The air is very thin here which gradually blends into outer space.

Question 4. What would have happened if there was no atmosphere around the earth?
Answer:

No atmosphere around the earth:

The following are a few consequences that would have happened without the atmosphere around Earth—

Without the atmosphere, there would have been no oxygen to breathe. Living organisms would not have survived.

The atmosphere controls the temperature and thus makes the Earth suitable for living. Without the atmosphere, the temperature on Earth would have been extreme.

The meteors that rush towards the Earth, burn up because of friction with the atmosphere. If the atmosphere was not present, meteors would have hit the surface of the Earth, causing damage to life and property.

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Question 5. Why does the sky appear red during sunrise and sunset?
Answer:

The sky appear red during sunrise and sunset:

Numerous dust particles, water vapour and water droplets remain suspended in the atmosphere.

As white sunlight enters the atmosphere, it collides with the suspended particles – this causes the scattering of sunlight.

Light with a shorter wavelength is scattered more. During sunrise or sunset, sunlight travels through a longer path in the atmosphere than during midday.

As a result, violet and blue light are scattered more than red. Thus, red and yellow light reaches straight to us and the sky appears red during sunrise and sunset.

Question 6. What are the characteristics of the Troposphere?
Answer:

The characteristics of the Troposphere are as follows:

1. The Troposphere extends to 16 km above the Earth’s surface.
2. This layer experiences rainfall, storms, tornadoes, cyclones and all other weather phenomena.
3. Temperature decreases with an increase in altitude. The average lapse rate is a drop of about 6.5°celsius for every 1,000-metre increase in altitude.

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Question 7. What are the characteristics of the Stratosphere?
Answer:

The characteristics of the Stratosphere are as follows:

1. The average extent of the Stratosphere is 50 km above the Earth’s surface.
2. This layer is devoid of water droplets and dust particles.
3. This layer does not experience rainfall, storms, tornadoes or cyclones.
4. Jet planes usually fly through this layer.
5. This layer is also known as the Ozonosphere because of the abundance of ozone at a height of about 20km – 25 km.

Question 8. What are the characteristics of the Thermosphere?
Answer:

The characteristics of the Thermosphere are as follows:

1. The average extent of the Thermosphere is about 300 km above the Earth’s surface.
2. The temperature rises rapidly in this layer. The temperature in this layer ofter shoots up to 200°C.
3. The layer is also known as the Ionosphere as the UV rays and X- rays ionise the gases in this layer.
4. Aurora op Polar lights are significant phenomena occurring in this layer.
5. Radio waves reflect back to the Earth from this layer thus facilitating wireless broadcasting.

Question 9. Define the crust, the mantle and the core.
Answer:

Crust: Crust is the topmost lighter part of the Lithosphere. It is composed of the SIAL and the SIMA.

Mantle: The layer in between the Crust and the core is known as the Mantle.

Some portions of the Mantle (Asthenosphere) are in a molten state where the convection currents flow.

Core: This is the innermost layer, that extends from after the Mantle to the centre of the Earth. This layer is formed by the heaviest metals such as iron and nickel. This is the hottest among all the layers.

 

 

Question 10. Write a short note on the Earth’s Crust.
Answer:

Earth’s Crust:

The outermost, solid layer of the Lithosphere is called the Crust. The average depth of continental crust is 60km and the oceanic crust is 5 km. Some features of this layer are:

Constituents: Mainly silica, aluminium, magnesium, etc.

Density: The average density is 2.9 grams/cubic cm.

Sub-layers: This layer is divided into SIAL (Si + Al) or the continental crust and SIMA (Si + Ma) or the oceanic crust.

The Conrad Discontinuity is the border between the upper continental crust and the lower one.

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Question 11. Write a short note on the Mantle.
Answer:

Mantle:

The layer between the Crust and the Earth’s Core is called the mantle. The average depth of this layer is 2900 km.

Constituents: Nickel, iron, silicon, chromium, magnesium, etc.

Density: The density of this layer is between 3.4-5.6gm/cubic cm.

Question 12. Write a short note on the Core.
Answer:

Core:

The innermost layer of the Earth is called the Earth’s Core. This layer extends from the lowermost part of the Mantle to the centre of the Earth. The thickness of this layer is about 3,500 km.

Constituents: Mainly nickel and iron.

Density: The density of this layer is between 9.9 -13.1 gm/cubic cm.

Sub-layers: The core can be further subdivided into the Outer core and Inner core. The Lehmann Discontinuity Line is the border between the Outer core and the Inner core.

Question 13. What is the importance of the Lithosphere in our lives?
Answer:

Lithosphere plays a significant role in our lives, such as:

Production of food: Soil forms when rocks disintegrate under the influence of climate. Plants cannot produce their food without soil. The food chain begins with green plants.

Source of minerals: Lithosphere is the source of all the metals and mineral resources such as copper, gold, etc.

Source of fossil fuels: Fossil fuels such as coal, petroleum, natural gas is obtained from the interior of the Earth.

Question 14. Define Hydrosphere.
Answer:

Hydrosphere:

One of the most important constituents of the Earth is water. Collectively all the water bodies on the Earth – like ponds, lakes, rivers, seas and oceans, ice-caps and glaciers together form the Hydrosphere.

This makes up about 71% of the Earth’s surface. Life on the Earth originated because of the presence of the Hydrosphere. The frozen part of the Earth’s Hydrosphere is known as Cryosphere.

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Question 15. What is the Water cycle?
Answer:

Water cycle:

The continuous movement of water in a cyclical manner from the surface of the Earth to the atmosphere and back again to the surface is called the Water cycle.

Water evaporates from waterbodies and then rises into the air as water vapour. When this vapour rises further into the cooler stretches of air,

water vapour condenses around dust particles to form water droplets and eventually several water droplets join to form clouds.

When the clouds become heavier than air due to the excessive content of water droplets, they cannot float around anymore, causing precipitation in the form of rain, snow, and hail.

Some of this water is absorbed by plants, and most of it reaches the Earth and flows through the rivers as surface discharge.

A part of this surface discharge also seeps underground as groundwater discharge. The water finally reaches the seas and oceans.

Evaporation starts all over again and this cycle continues. So, another way of defining the Water cycle is as the never-ending cycle of evaporation, condensation and precipitation that maintains the total volume of water on Earth (in various physical states) at a constant.

 

 

Question 16. State the importance of water in our daily lives.
Answer:

Water is important in the following ways:

Day-to-day activities: Water is required for our day-to-day activities such as drinking, bathing, washing, cleaning, cooking and others.

Agriculture and industries: In agriculture, water is required for irrigation. A large amount of water is also required in factories and industries.

Transportation: Water transport is the cheapest mode of transport. So, throughout the world, waterways are used to transport goods.

Question 17. How would your experience be, seated in a rocket, journeying to outer space?
Answer:

When I ascend to the sky by rocket, I will continue through the clouds. Gradually, the houses underneath will appear smaller. If I go up about 10 km, nothing will be seen below.

The forest will all become obscure. The cloud level is much lower now and the sky above is dark blue. If I go higher, the blue sky will be lost.

Then the sky will turn purple. If I reach about 80 km the sky will be black, as like the night sky. In that sky, the Sun, the stars, and the plants can be seen. And that is our Earth, a bright blue sphere in the black sky.

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Question 18. How does rainfall occur?
Answer:

Rainfall occur:

Water evaporates from the rivers, water bodies and seas due to the intense heat of the Sun and mixes with the air. Water vapour is lighter than air.

So the air with water vapour rises upwards. The water vapour floating in the air is condensed and turns into water particles. These water particles float as clouds being sheltered by the dust particles in the air.

The smaller water particles floating in the clouds combine to form larger water particles. These larger water particles are heavier than air and can no longer float. Then the floating water droplets fall on the Earth in the form of rain. Thus rainfall occurs on Earth.

Chapter 5 Water Land Air Topic A The Earth Its Atmosphere, Lithosphere And Hydrosphere Short Answer Type Questions

Question 1. What is the atmosphere and what is its extent?
Answer:

Atmosphere:

The blanket of air that envelopes the Earth and is held close to it because of the Earth’s gravitational pull is called the Atmosphere.

It is made up of various gases, water vapour and aerosols. The atmosphere extends up to a height of about 1000 km above the surface of the Earth.

Question 2. What is the atmosphere made up of?
Answer:

The atmosphere is made up of three main kinds of constituents. These are:

1. Gases—Nitrogen, oxygen, carbon dioxide, argon, hydrogen, helium, ozone and others;
2. Water vapour;
3. Aerosols—Dust particles and salt particles. Apart from this, it also contains some impurities as well as some living organisms.

Question 3. Mention the main gaseous components of the atmosphere.
Answer:

The main gaseous components of the atmosphere are:

Nitrogen(N₂), Oxygen (O₂), Carbon dioxide (CO₂), Argon (Ar), Neon (Ne), Helium (He), Hydrogen (H₂), Methane (CH₄), Ozone (O₃), Krypton (Kr), Xenon (Xe).

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Question 4. What is the significance of dust particles in the atmosphere?
Answer:

Significance of dust particles in the atmosphere:

The dust particles present in the atmosphere form the nucleus for condensation – this means, water vapour gathers around the dust particles to form clouds which result in rainfall or snowfall.

Dust particles also absorb heat from the Sun’s rays, thus helping to control the temperature of the Earth’s surface. Dust particles also scatter red light from the sun’s rays.

Thus when there are more pollution or dust particles in the air, the sky appears redder.

Question 5. How does the Troposphere influence weather conditions?
Answer:

The Troposphere influence weather conditions:

The Troposphere is the lowest layer of the atmosphere and the nearest to the Earth’s surface.

All the weather phenomena like clouds, fog, rainfall, snowfall, storms and lightning are visible in this layer due to the presence of suspended dust particles and water droplets.

This is the densest layer of the atmosphere. It absorbs the heat radiating from the Earth’s atmosphere and keeps the Earth warm.

Question 6. Why is the Troposphere also known as the ‘Sphere of Turning’?
Answer:

The Troposphere also known as the ‘Sphere of Turning’:

The lowest atmospheric layer, extending 16 km above the Earth’s surface, is the Troposphere.

This layer is also called the ‘Sphere of Turning’ because this turbulent, chaotic zone is full of air currents, clouds, storms and other weather phenomena.

All this happens because this layer has suspended dust particles and water droplets in it.

Question 7. Through which layer of the atmosphere do jet planes fly and why?
Answer:

Jet planes usually fly through the second layer of the atmosphere the Stratosphere.

This is because no weather phenomenon is found in this layer and so jet planes face no disturbance while flying.

Weather phenomena are not noticed here because water vapour is absent in this layer.

So clouds, storms or lightning are not seen in this layer. The temperature remains constant and there are no convection currents of air.

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Question 8. What Is Ozonosphere? What are the benefits of Ozonosphere? Or, ‘Ozonosphere acts as a protective shield for the Earth’s biosphere.’-Explain.
Answer:

The Stratosphere is also known as the Ozonosphere, because of the high concentration of ozone gas in this layer.

The Earth’s atmosphere is blanketed by a 3-4 km thick layer of ozone that is a part of this layer.

Ozonosphere extends from 20 km above the Earth’s surface to about 25 km and acts as a protective shield for all the living beings on the Earth.

Benefits: All the benefits of the Ozonosphere are as follows-

1. The ozone in this layer absorbs the harmful Ultraviolet radiation from the Sun and thus protects all living beings on Earth.
2. Ozone controls the Earth’s temperature.

Question 9. What is the Thermosphere? What is the extent of this layer? i+i
Answer:

Thermosphere:

The Thermosphere is one of the upper layers of the Earth’s atmosphere.

This extends about 300km from the Earth’s surface, above Mesosphere. In this layer, the temperature increases with an increase in altitude.

The air in this layer is so thin that, it almost does not exist. So the sky appears black when seen from this layer.

Question 10. The Thermosphere is also known as Ionosphere—why?
Answer:

The Thermosphere is also known as Ionosphere:

The layer of air extending from 80km-300km above the Mesosphere is called the Thermosphere. High energy waves such as UV, Gamma (y) and X- rays are radiated from outer space.

These rays strike the Thermosphere to ionise the gases present there to form ions. Thus, the Thermosphere is also known as the Ionosphere.

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Question 11. Which layer of the atmosphere reflects radio waves back to the Earth? What happens as a result of this? 
Answer:

The Thermosphere or Ionosphere reflects radio waves back to the Earth.

This layer contains gases in the ionised state which reflect radio waves back. This makes it possible for us to have wireless communication.

Question 12. What is Exosphere?
Answer:

Exosphere:

The layer of air extending almost up to 1500 km above the Thermosphere is called the Exosphere. This layer is rich in helium and hydrogen.

In this layer, the temperature rises with an increase in altitude. Artificial satellites and Space stations are often located in this layer.

Question 13. What are the different layers of the Earth and what are their extents?
Answer:

The different layers of the Earth are as follows:

Crust: From 0-30km below the Earth’s surface. Mantle: From 30 km-2900 km below the Earth’s surface.

Core: From 2900 km-6370km below the Earth’s surface.

Question 14. What is Lithosphere?
Answer:

Lithosphere:

The lithosphere is the solid, rocky outer part of the Earth, which is made up of various types of rocks.

Lithosphere comprises the Crust and the Upper mantle. The Lithosphere is divided into several plates—the Continental plates and the Oceanic plates.

Question 15. What is the Hydrosphere?
Answer:

Hydrosphere:

One of the most important constituents of the Earth is water. Collectively, all the water bodies on the Earth – ponds, lakes, rivers, seas and oceans together form the Hydrosphere.

This makes up about 71% of the Earth’s surface. Life on Earth originated because of the presence of the Hydrosphere.

Question 16. Why does the Earth appear blue from outer space?
Answer:

71% of the Earth is covered by water, which gives it a blue appearance from outer space.

Chapter 5 Water Land Air Topic A The Earth Its Atmosphere, Lithosphere And Hydrosphere Multiple Choice Questions

Question 1. The blanket of air that surrounds the earth and extends up to almost 10000 km above the earth’s surface is called the—

1. Hydrosphere
2. Lithosphere
3. Atmosphere

Answer: 3. Atmosphere

Question 2. The main gaseous component of the atmosphere is—

1. Nitrogen
2. Oxygen
3. Carbon dioxide

Answer: 1. Nitrogen

Question 3. The percentage of nitrogen in the atmosphere is almost—

1. 20%
2. 78%
3. 3%

Answer: 2. 78%

Question 4. The percentage of oxygen in the atmosphere is almost—

1. 21%
2. 78%
3. 3%

Answer: 1. 21%

Question 5. The main gaseous constituent of the atmospheric layer i.e. Available 20 km-25 km above the earth’s surface is—

1. O2
2. O3
3. N02

Answer: 2. O3

Question 6. The layer of the atmosphere that extends up to 16km above the earth’s surface is called the—

1. Troposphere
2. Stratosphere
3. Mesosphere

Answer: 1. Troposphere

Question 7. The layer that sees an abundance of weather phenomena, like storms and rain is the—

1. Troposphere
2. Stratosphere
3. Mesosphere

Answer: 1. Troposphere

Question 8. Harmful ultraviolet rays are absorbed in the—

1. Mesosphere
2. Ozonosphere
3. Exosphere

Answer: 2. Ozonosphere

Question 9. Jet planes travel through—

1. Ozonosphere
2. Stratosphere
3. Mesosphere

Answer: 2. Stratosphere

Question 10. The layer that reflects radio waves back towards the earth’s surface is the—

1. Ionosphere
2. Mesosphere
3. Exosphere

Answer: 1. Ionosphere

Question 11. The number of meteors that rush towards the earth every day is—

1. 10 Billion
2. 150 Billion
3. 200 Billion

Answer: 1. 10 Billion

Question 12. The thin, hard outermost layer of the earth is called the—

1. Core
2. Crust
3. Mantle

Answer: 2. Core

Question 13. The innermost layer of the earth is—

1. Crust
2. Core
3. Mantle

Answer: 2. Core

Question 14. Life on earth first originated—

1. On land
2. In air
3. In water

Answer: 3. In water

 

Chapter 5 Water Land Air Topic A The Earth Its Atmosphere, Lithosphere And Hydrosphere Fill In The Blanks

Question 1. The earth’s force holds Earth’s____________ atmosphere in the place.
Answer: Gravitational

Question 2. At the time of sunset and sunrise, the sky appears ____________
Answer: Reddish

Question 3. The layer of the atmosphere closest to the Earth’s surface is the____________
Answer: Troposphere

Question 4. Temperature decreases with an increase in altitude in the ____________ layer of the lower atmosphere.
Answer: Troposphere

Question 5. Almost 97 per cent of the wind systems exist within the first____________ km above the Earth’s surface.
Answer: 27

Question 6. The layer of atmosphere that extends about 80 km above the Earth’s surface is called the____________
Answer: Mesospehere

Question 7. The temperature in the____________ layer of the atmosphere is almost 200°Celsius.
Answer: Ionosphere

Question 8. layer of the atmosphere right after Thermosphere is the ____________
Answer: Exosphere

Question 9. If the____________ was not there, there would have been a sharp drop in temperature right after sunset and a sharp rise in temperature just after sunrise.
Answer: Atmosphere

Question 10. The____________ cycle maintains the total amount of water on Earth.
Answer: Water

Question 11. The innermost part of the Earth is still____________
Answer: Extremely hot

Question 12. The Earth’s core is made up of heavy iron and ____________
Answer: Nickel

Question 13. The solid landmass, made up of mostly rocks and soil, is known as ____________
Answer: Lithosphere

Question 14. Life first originated on Earth about____________ billion years ago.
Answer: 3.5

Question 15. About ____________ billion years ago when the Earth was first formed, it was a swirling ball of fiery gases.
Answer: 5

Question 16. The temperature of the Earth has been decreasing from about____________ billion years ago.
Answer: 3.8

Question 17. Plants make their own food by taking nutrients from the____________
Answer: Soil

Question 18. Coal, petroleum and natural gases are____________ fuels.
Answer: Fossil

Question 19. ____________ is also called liquid gold,
Answer: Petroleum

Question 20. ____________ is also called a black diamond.
Answer: Coal

Chapter 5 Water Land Air Topic A The Earth Its Atmosphere, Lithosphere And Hydrosphere Write True Or False

Question 1. The stratosphere extends for 50 km above the Surface of the Earth.
Answer: True

Question 2. The layer above the Thermosphere is called the Tropopause.
Answer: False

Question 3. With the increase in altitude in the Stratosphere, the temperature decreases.
Answer: False

Question 4. Northern Lights occur in the Ionosphere.
Answer: True

Question 5. The upper reaches of the Troposphere lead to Mesopause.
Answer: False

Question 6. The last layer of the atmosphere is called Exposure.
Answer: True

Question 7. The blanket of air that envelopes the Earth is called the Hydrosphere.
Answer: False

Question 8. The layer above the Core is called the Mantle.
Answer: True

Question 9. Neon is an inactive gas.
Answer: True

Question 10. The cyclic movement of water is called the Water cycle.
Answer: True

Question 11. The meteors burn in the thermosphere.
Answer: False

Question 12. SIAL is a part of Crust.
Answer: True

Question 13. The main components of the Core are nickel and iron.
Answer: True

Chapter 5 Water Land Air Topic A The Earth Its Atmosphere, Lithosphere And Hydrosphere Answer In One Or Two Words

Question 1. What is the extension of the atmosphere from the Earth’s surface?
Answer: 1000 km.

Question 2. What is the main gaseous component of the atmosphere?
Answer: Nitrogen.

Question 3. In which layer the Ozonosphere is located?
Answer: Stratosphere.

Question 4. What is the thickness of the Ozonosphere?
Answer: 4km-5km.

Question 5. In which layer the UV rays are being absorbed?
Answer: Ozonosphere.

Question 6. What is the extension of the Mesosphere?
Answer: 50 km – 80 km.

Question 7. From which atmospheric layer do Radio waves reflect back to the Earth?
Answer: Ionosphere.

Question 8. What is the estimated age of the Earth?
Answer: Almost 5 billion years.

Question 9. What is the name of the ancient supercontinent?
Answer: Pangaea.

Question 10. Write the name of the outermost layer of the Earth.
Answer: Crust.

Question 11. what is the thin, hard, outermost layer of the Earth’s surface called?
Answer: Crust.

Question 12. What layer of the Earth provides mineral resources?
Answer: Lithosphere.

Question 13. Is there water on any other Planet in the solar system?
Answer: No.

Question 14. Do you think plants and animals could have survived without air?
Answer: No.